Stable floating device for reducing evaporation in open pools

ABSTRACT

This invention corresponds to a flotation device comprising a cylindrical body having perimetral flotation cavities; a predetermined quantity of air deposited and enclosed in each of such cavities; and covers to cover said cavities.

FIELD OF THE INVENTION

The invention is intended to reduce the evaporation in open lagoons.

This invention relates to a device useful in reducing evaporation in open lagoons.

This invention comprises a floating device that meets the restrictions required by large-scale mining such that it diminishes evaporation in open lagoons and withstands climatic and atmospheric conditions in the large-scale mining zone.

BACKGROUND OF THE INVENTION

There is an ongoing problem in mining companies and in agriculture because of the evaporation of water stored in lagoons or dams when environmental temperatures are high. This problem is becoming increasingly important because of the scarcity of fresh water in industrial zones and the great need to use fresh water in mining and farming.

Evaporation in this type of body of water is controlled, for example, by chemical canopies consisting of dumping a chemical into the stored water so that the chemical forms a liquid film above the water; floating covers made of floating synthetic film that cover the entire area of exposed water; superposed covers consisting of floating synthetic covers that are held up by structures; or floating objects consisting of multiple individual objects that are placed on the exposed area of the water and float beside each other.

Document US2008000903 describes a modular floating cover for a water storage consisting of a plurality of modules in which each module includes a chamber defined by an upper surface and a lower surface, there being openings in the upper surface to allow ingress of water into the chamber and openings in the upper surface to allow air to flow into and out of the chamber depending on the water level within that chamber so that each module floats independently. The size of the module is selected to ensure that the module is stable in high wind conditions and that stacks of modules are not formed. The modules may be hexagonal or octagonal.

Document WO2011035362 describes a module forming part of a floating modular cover, including an upper shell, a lower shell, a chamber defined by the upper and lower shells, a water ingress opening in the lower cover to allow ingress of water to the chamber for ballast and an opening in the upper shell to allow air to flow into and out of the chamber and a plurality of discrete flotation cells for ensuring flotation of the module, wherein the upper shell and lower shell, when the module is in an assembled state, act to house each flotation cell in a predetermined position within the chamber.

Document WO2010083560 describes a module forming part of a floating cover for water, including an upper shell, a lower shell and a chamber defined by the upper and lower shells; one or more water ingress openings in the lower shell to allow ingress of water into the chamber; one or more air openings in the upper shell to allow air to flow into and out of the chamber depending on the water level within the chamber; one or more first securing openings in the lower shell; one or more second securing openings in the upper shell; and a plurality of flotation cells for ensuring flotation of the module. Each flotation cell is insertable through a pair of first and second securing openings and cooperating with the first shell wall portions surrounding each pair of first and second securing openings to retain the module in an assembled state.

Document US2007275616 describes a floating water surface cover module comprising a rim and a shallow dome-shaped cover extending from the top of the rim and formed with a vent, the rim and cover being formed with shaped air-filled cavities spaced around the rim to provide buoyancy, the rim and shallow cover being configured so that one module is nested within another to form a stable stack.

As seen, the investigations in the prior art have focused generally on developing different types of modules that entail the ingress and egress of water and ingress and egress of air to allow the module to float.

However, there is still a need to have more stable floating modules or floating devices that are capable of withstanding and dissipating disturbances caused by wind on the surface of a lagoon and by more extreme weather conditions, while reducing or controlling evaporation in open lagoons by forming a physical barrier that protects the lagoon from solar radiation and the action of wind.

This invention consists of a floating device that is stable, low cost, dissuasive to migratory birds, made of resistant material, easily transportable, installable and removable (for example, to perform maintenance), and allows small boats to navigate freely on the surface of the lagoon.

One objective sought by implementing the device in this invention is for a set of devices in this invention to be capable of forming a physical barrier covering the surface of the lagoon in order to reduce evaporation. The objective is to cover less than 100% of the lagoon surface but more than 90% of the lagoon surface.

Another objective of this invention is for each device to float at the same predetermined level so that each device remains stable under adverse weather conditions, for example wind pressure, and does not sink by the effect of adjacent devices.

Another objective of this invention is also for the device to adapt to the change in surface because of waves, keeping the waves from passing over the device or bursting over the device, thus diminishing evaporation.

Another objective of this invention is for each device to have a suction effect so as to create a resistance to any wind that attempts to lift it off the surface of the lagoon, for example by lifting it and blowing it far from the surface of the lagoon. The suction effect keeps the device from turning over. If one of its edges leaves the water, the device is re-stabilized immediately by the suction effect.

SUMMARY OF THE INVENTION

This invention corresponds to a floating device, including a cylindrical body having perimetral flotation cavities; and a predetermined quantity of air deposited and enclosed in each of such cavities; and covers to cover such cavities.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described below with reference to the attached drawings in which:

FIG. 1 is a perspective view of the underside of the floating device in this invention.

FIG. 2 is a perspective view of the upper side of the floating device in this invention, some of its covers having been installed and showing some of its cavities.

FIG. 3 is a plan view of the floating device in this invention.

FIG. 4 is a side view of the floating device in this invention.

FIG. 5 shows a cross-section of the stacking of two floating devices in this invention.

FIG. 6 shows a close-up of the cross-section in FIG. 5.

DETAILED DESCRIPTION OF THE INVENTION

This invention corresponds to a floating device formed by a cylindrical body (6) having at least eight perimetral cavities (7); at least 8 covers (8) to cover those cavities; and a predetermined quantity of air deposited and enclosed in each of such cavities in the cylindrical body.

The cylindrical body (6) is formed by a pyramidal cover (1) that has a rounded outside edge; at least eight perimetral cavities (7) that surround the entire rounded edge of the pyramidal cover (1), wherein the cavities are open toward the top of the cylindrical body and have a closed, flat bottom (2); a perpendicular sidewall (3) along the entire perimeter of the cylindrical body (6); a central opening (4); and at least six radial structural ribs, preferably at least eight radial structural ribs (5) located in the bottom of the pyramidal cover (1). The pyramidal shape of the cover (1) allows that cover to be higher in the center. Each of the eight structural ribs starts from the rim of the central opening and extends radially until butting up against the interior rim of the perimetral cavities. Those structural ribs have a depth or height of approximately 3 cms and a length that ranges from approximately 39 cm to approximately 63 cm, the preferred value being approximately 49 cm. They are also located at the bottom of the pyramidal cover, are made of a solid material, preferably polyethylene. The sidewall (PL) also has a height that ranges from approximately 10 cm to approximately 20 cm.

There are at least 8 perimetral cavities, more preferably 16, and each has a depth or height that ranges from approximately 3 cm to approximately 5 cm, where the preferred value is approximately 4 cm; and a width radial to the cylindrical body that ranges from approximately 6 cm to approximately 12 cm, the preferred value being approximately 7 cm or even more preferably approximately 9 cm. The volume of air within all the perimetral cavities ranges from approximately 10,500 cm³ to approximately 13,500 cm³ and preferably totals approximately 11,500 cm³, even more preferably approximately 12,000 cm³. The covers over the cavities are flat and are welded to such perimetral cavities so that the air is trapped inside the cavities and there are no leaks, each cover preferably covering at least 2 perimetral cavities. The covers are in the shape of a section of the perimetral rim of the cylindrical body where the width radial to the cylindrical body is from approximately 6 cm to approximately 12 cm, the preferred value being approximately 7 cm or even more preferably approximately 9 cm. Each cover has a surface thickness of approximately 2 mm and has two lower ribs, one located along the width of each of the ends of the cover so that the thickness of the cover at the ends can be increased to approximately 2.5 mm. The air in each of the cavities allows the device to stay afloat. It is important that the quantity of air in each of the cavities be the same so that the device remains stable on the lagoon surface. The volume of air will also depend on the weight of the device since the thrust by the group of perimetral cavities has been determined to be in a range of approximately 2.5 to 3.5 times the device's weight. This leads to the conclusion that the quantity of air is determined by the following ratio:

Air volume (cm³)=device weight (Kg)*3,000 (cm³/Kg)

where the weight of the device is approximately from 3.5 to 4.5 kilograms.

The pyramidal cover is defined by least 8 triangular sections that rise in the form of a pyramid from the interior rim of the perimetral cavities at an elevation of approximately 7 degrees from an imaginary horizontal plane as far as the rim of the central opening, each of said triangular sections having equal sides and each side having a length that varies from approximately 39 cm to approximately 63 cm, the preferable value being 53 cm, even more preferably approximately 49 cm.

Additionally, the floating device must have an appropriate suction force for such device to remain afloat and in position wherefore the device suction force depends on the total diameter of the device (D) (FIG. 4), on the height of the device sidewall (PL), on the diameter of the device central opening (d) and on the height of the device flotation level, defined as height F in FIG. 4, which corresponds to the section that is not below water, meaning the section of the device that is floating. It has therefore been established that such variables must meet the following ratio for the device to have an appropriate suction force.

[(D/2̂2]*π*(PL−F)≧120.000*d

where the units of measure of each of the variables are expressed in centimeters.

The diameter (D) of the floating device has a value that ranges from approximately 90 cm to approximately 150 cms, preferably approximately 130 cm and more preferably approximately 116 cm; and the height of the sidewall of the floating device (PL) varies from approximately 10 cm to approximately 20 cm, its preferred measurement being approximately 10 cm to 16 cm, even more preferably approximately 14 cm. The diameter of the central opening of the floating device (d) also varies from approximately 0.47 cm to approximately 2.30 cm, most preferably from approximately 0.8 cm to 1.5 cm, and the diameter is preferably approximately 1 cm; while the height of the flotation level (F) of the floating device measures from approximately 1 cm to approximately 4 cm, the preferred value being approximately 3 cm, even more preferably approximately 2.6 cm.

The device is manufactured by plastic injection into a chemically inert material such as, for example, high-density polyethylene (HDPE). The exterior shape of the devices also allows them to be stackable.

The lower edge of the sidewall of the device must be blunt (9) so that the device will pose no risk of cutting the different types of membranes covering the walls and the bottom of lagoons, such as the geotextile layer that protects the sidewalls and the bottom of lagoons. This is also so that there is less of an undermining effect against walls that are not lined with membranes.

FIG. 1 shows a perspective view of the bottom of the floating device in which the bottom of the pyramidal cover (1), the structural ribs (5) that give the floating device firmness, the central opening (4), the smooth bottom of the perimetral cavities (2) and the sidewall (3) of the device can be seen.

FIG. 2 shows a perspective view of the top of the floating device in which the top of the pyramidal cover (1), the central opening (4), the sidewall (3) of the device, the perimetral cavities (7) and the covers (8) of such cavities can be seen.

FIG. 3 shows the plan view of the floating device in which the perimetral cavities (7) can be seen.

FIG. 5 shows a cross-section of two stacked floating devices in this invention in which it can be seen that one device is supported on another when the bottom of the perimetral cavities of a device butt up against the top of the covers of the perimetral cavities of the other device.

FIG. 6 shows a close-up of FIG. 5 in which the bluntness (9) of the lower edge of the sidewall can be seen, which keeps membranes, i.e., geotextiles, from being cut.

As can be seen, the floating devices are also designed to facilitate stacking one on top of the other when they are not being used. The devices can also be used in acid ponds since the preferred material for their manufacture is high-density polyethylene.

When they are in use, the floating devices in this invention will form a physical barrier covering the surface of the lagoon, which will reduce evaporation. If the floating devices are installed on the entire surface of the lagoon, the physical barrier is estimated to cover approximately 90% of the lagoon surface. Please note that it is not convenient for 100% of the lagoon surface to be covered in order to keep the liquid from stagnating and to keep microorganisms from proliferating. The physical barrier must also allow small boats to circulate on the surface of the lagoon and for an easy removal of the devices to allow lagoon maintenance.

Moreover, the floating devices in this invention have the advantage of being stable since the perimetral cavities in the devices contain a predetermined quantity of trapped, enclosed air, said air being completely enclosed since the perimetral cavities have welded covers to keep air from escaping. The structural technical features of this device allow the device to return to its initial position and maintain its flotation level in the face of abrupt movements. Since it has several cavities, the air is distributed uniformly throughout the perimetral rim, keeping the air trapped and enclosed in the device from escaping if there is a potential structural failure in one of the cavities.

EXAMPLE

Below is a description, by way of example, of a flotation device made of high-density polyethylene for use in open lagoons, having a total diameter of 116 cm; 16 cavities; 8 structural ribs; a central opening 1 cm in diameter; a sidewall height of 14 cm; and a flotation height of 2.65 cm. The flotation device weighs 4 kilograms, so the total volume to be put inside all the cavities is 12,000 cm³. 

1. A flotation device stable under adverse weather conditions that reduces evaporation in open lagoons, COMPRISING: A cylindrical body (6) having at least eight perimetral cavities (7); at least eight covers (8) to cover the perimetral cavities; and a predetermined quantity of air deposited and enclosed in each of such cavities in the cylindrical body.
 2. The floating device according to claim 1 wherein the cylindrical body (6) is formed by a pyramidal cover (1) that has a rounded exterior edge; the perimetral cavities (7), which surround the entire rounded edge of the pyramidal cover (1), wherein the cavities are open toward the top of the cylindrical body and the bottom of such cavities (2) is closed and flat; a perpendicular sidewall (3) along the entire perimetral edge of the cylindrical body; a central opening (4); and at least six radial structural ribs, preferably at least eight radial structural ribs (5) located in the bottom of the pyramidal cover (1).
 3. The floating device according to claim 2 wherein the sidewall has a height that varies from approximately 10 cm to approximately 20 cm.
 4. A floating device according to claim 1, wherein the perimetral cavities preferably number 16 and wherein each cover covers 2 perimetral cavities; and wherein such cavities have a depth that ranges from approximately 3 cm to approximately 5 cm and a width radial to the cylindrical body that ranges from approximately 6 cm to approximately 12 cm.
 5. The flotation device according to claim 1, wherein the total quantity of air that is deposited and enclosed in all cavities ranges from approximately 10,500 cm³ to approximately 13,500 cm³.
 6. The floating device according to claim 2, wherein the lower edge of the sidewall (9) is blunt, i.e., it has no point.
 7. The floating device according to claim 2, wherein the central opening has a diameter measuring from approximately 0.47 cm to approximately 2.30 cm and the diameter of the floating device varies from approximately 90 cm to approximately 150 cm.
 8. The flotation device according to claim 1, wherein the flotation device is made of polyethylene, most preferably high-density polyethylene.
 9. The flotation device according to claim 1, wherein each cover has a thickness of approximately 2 mm on the surface and 2 lower ribs, one located along the width of each of the ends of each cover so that the thickness of the cover can be increased at the ends to a value of approximately 2.5 mm; and wherein said covers are welded on the perimetral cavities to keep air from leaking from said cavities.
 10. The flotation device according to claim 5 wherein the weight of the device is approximately 3.5 to 4.5 kilograms and the total air volume is dependent upon the weight of the device, such weight and volume meeting the following ratio: Air volume (cm³)=device weight (Kg)*3,000 (cm³/Kg)
 11. The flotation device according to claim 2 wherein each of the radial structural ribs (5) located in the bottom of the pyramidal cover (1) have a depth or height of approximately 3 cm and a length varying from approximately 39 cm to approximately 63 cm. 